1. Field of the Invention
This invention relates generally to web treating systems and, more particularly, to methods and apparatus for handling and coating of either one or two sides of an inked web.
2. Description of the Prior Art
Coating printed webs provides protection to the printed surface of the web and can enhance the appearance of the printed material on the web by forming a gloss on the surface of the printed surface.
It is conventional to apply such a coating to the printed web after the ink on the web has dried so that there is no concern in known devices regarding smudging or offset of wet ink on the coating rollers. Following coating, the coated web is dried and the printed and coated article is complete.
One disadvantage with such a system is that the web must undergo two drying operations during the process. This involves additional time and expense so that it would be desirable to be able to apply both ink and coating to the web prior to any drying operation so that both the ink and coating could be dried in a single drying operation.
It is known in the prior art that this objective may be achieved in a two side coating system including a rubber coating applicator roller, a rubber back-up roller and means for supplying both of the rollers with coating so that a web passing between the rollers is coated on both sides thereof. However, it has not been possible to adapt this system for use in a one side coating operation since offset and smudging occur at the back-up roller when coating is not being supplied thereto.
There is a need for a coating system which is capable of performing a one or two side coating operation on a web having wet ink on both sides thereof which prevents smudging and offset of the wet ink to the back-up roller.
In addition, there is a further need for a turning roller structure that can be used in either coating or printing operations to guide a freshly inked web into an operation subsequent to printing without a risk of smudging of the ink.